Conventionally, resin composites and molded bodies of these resin composites are made lighter by adding hollow glass microspheres to a resin material. Furthermore, methods of processing the hollow glass microspheres that are added to the resin material have been investigated in order to improve the mechanical properties of the resin composite and molded bodies of the resin composite.
Japanese Unexamined Patent Application Publication No. H5-139783 discloses hollow glass microsheres coated with a resin, and a composition for molding that contains the hollow glass microsheres, containing a matrix resin and a thermoplastic elastomer with a flexural modulus of 100 to 1200 kg/cm2.
Japanese Unexamined Patent Application Publication No. H5-171032 discloses a reinforced thermoplastic resin composition which contains a resin compound where modified polyethylene ether resin forms a dispersion phase and a polyamide resin (b) forms a continuous phase, glass fiber (Y) having aminosilane treated surfaces, and hollow glass microsheres, wherein the glass fibers are coated by the modified polyphenylene ether resin. Japanese Unexamined Patent Application Publication No. 2007-517127 discloses a thermoplastic resin composite with a filling material, containing at least one type of polyamide, and glass bubbles with a crushing strength of at least 10,000 PSI that have been treated with at least one of a silane coupling agent or a titanate coupling agent.
When hollow glass microspheres are added to a resin material, the material can be made lighter, but on the other hand, there is a tendency for mechanical properties such as specific tensile strength, specific flexural strength, and the like of an obtained resin composite or of a molded body made from this resin composite to be inferior. Therefore, attempts have been made to treat surfaces of the hollow glass microspheres with a silane coupling agent. The mechanical properties required in the fields of electronic components and automotive components may not be achievable with such surface treatments.